The demand for increased bandwidth in wireless networks has been relentless the past several years and shows no signs of abating. Fortunately, Airgo Networks, Inc. of Palo Alto, Calif. is developing products for wireless networks that meet these demands. In fact, these products have reached an important threshold. Networks developed by Airgo are the first to achieve the 100 Mbit data rates needed for streaming video for home entertainment and other high data-rate applications. To achieve this incredible data rate, significant improvements over conventional circuits and techniques have been developed.
Among these significant improvements are reductions in overhead required by wireless protocols. One such source of overhead in need of reduction involves the contention period where one or more stations in a wireless network vie for access to the wireless medium.
In order to avoid collisions in a wireless network, stations that need to transmit data are not allowed to transmit immediately once the network is silent. Rather, each station that needs to transmit data is required to wait a certain period of time chosen at random from a set of possible times. After this time has passed, if the channel is still silent, the station may transmit data. This process is referred to as a channel contention.
This wait time is time wasted; it is time that is not used to transmit data. Thus, what is needed are circuits, methods, and apparatus that reduce the occurrence of these channel contentions. It is also desirable that these circuits, methods, and apparatus be compatible with the inclusion of legacy devices in a network. For example, new protocols for reducing wasted time on the medium may be implemented by HT WLAN devices (high-throughput wireless LAN) while sharing the medium with legacy 11a/b/e/i/g WLAN devices. Thus, what is additionally needed are circuits, methods, and apparatus that provide signaling mechanisms to control new efficient protocols within the context of existing networks, in particular existing 802.11 networks.